#include "FieldCircuitCoupling.h"
#include <fstream>
#include <iomanip>
#include <math.h>
#include <stdexcept>
#include <sstream>
#include <unordered_map>
#define _USE_MATH_DEFINES
#include <math.h>

namespace FieldCircuitCoupling {

// CircuitModel implementation
CircuitModel::CircuitModel() : initialized(false), currentFrequency(0.0) {
}

CircuitModel::~CircuitModel() {
}

bool CircuitModel::addElement(const CircuitElement& element) {
    if (initialized) {
        return false;  // Cannot add elements after initialization
    }
    elements.push_back(element);
    if (element.type == CircuitElementType::PORT) {
        ports.push_back(element);
    }
    return true;
}

bool CircuitModel::initialize() {
    buildNodeMap();
    initialized = true;
    return true;
}

bool CircuitModel::updateFrequency(double frequency) {
    if (!initialized) {
        return false;
    }
    currentFrequency = frequency;
    return true;
}

bool CircuitModel::getImpedanceMatrix(std::vector<std::vector<Complex>>& Z_circuit) {
    if (!initialized) {
        return false;
    }
    
    size_t numNodes = nodeNames.size();
    Z_circuit.resize(numNodes, std::vector<Complex>(numNodes, 0.0));
    
    // Initialize matrix to zero
    for (size_t i = 0; i < numNodes; ++i) {
        for (size_t j = 0; j < numNodes; ++j) {
            Z_circuit[i][j] = 0.0;
        }
    }
    
    // Stamp each element into the matrix
    for (const auto& element : elements) {
        stampMatrix(Z_circuit, element);
    }
    
    return true;
}

bool CircuitModel::setPortVoltages(const std::vector<CouplingPort>& ports, 
                                  const std::vector<Complex>& voltages) {
    if (ports.size() != voltages.size()) {
        return false;
    }
    
    // Implementation would update the circuit model with the port voltages
    // This is typically done by modifying the right-hand side vector
    return true;
}

bool CircuitModel::getPortCurrents(const std::vector<CouplingPort>& ports, 
                                  std::vector<Complex>& currents) {
    // Implementation would extract the port currents from the circuit solution
    currents.resize(ports.size(), 0.0);
    return true;
}

bool CircuitModel::solve(const std::vector<std::pair<int, Complex>>& boundaryConditions) {
    // Implementation of circuit solver
    // For simplicity, this is a placeholder
    return true;
}

bool CircuitModel::exportSolution(const std::string& filename) {
    try {
        std::ofstream file(filename);
        if (!file.is_open()) {
            return false;
        }
        
        file << "Circuit Solution at Frequency: " << currentFrequency << " Hz\n";
        file << "Node Voltages:\n";
        
        // Export node voltages (placeholder)
        for (size_t i = 0; i < nodeNames.size(); ++i) {
            file << "Node " << nodeNames[i] << ": 0.0 + j0.0 V\n";
        }
        
        file << "Element Currents:\n";
        // Export element currents (placeholder)
        
        file.close();
        return true;
    } catch (...) {
        return false;
    }
}

bool CircuitModel::importFromFile(const std::string& filename) {
    try {
        std::ifstream file(filename);
        if (!file.is_open()) {
            return false;
        }
        
        std::string line;
        while (std::getline(file, line)) {
            if (line.empty() || line[0] == '#') {
                continue;  // Skip comments and empty lines
            }
            
            std::istringstream iss(line);
            CircuitElement element;
            std::string typeStr;
            
            if (!(iss >> element.id >> typeStr >> element.node1 >> element.node2)) {
                continue;  // Invalid line format
            }
            
            // Parse element type
            if (typeStr == "R") {
                element.type = CircuitElementType::RESISTOR;
            } else if (typeStr == "C") {
                element.type = CircuitElementType::CAPACITOR;
            } else if (typeStr == "L") {
                element.type = CircuitElementType::INDUCTOR;
            } else if (typeStr == "V") {
                element.type = CircuitElementType::VOLTAGE_SOURCE;
            } else if (typeStr == "I") {
                element.type = CircuitElementType::CURRENT_SOURCE;
            } else if (typeStr == "PORT") {
                element.type = CircuitElementType::PORT;
            } else {
                continue;  // Unknown element type
            }
            
            // Parse element value
            double realPart, imagPart = 0.0;
            if (iss >> realPart) {
                if (iss >> imagPart) {
                    element.value = Complex(realPart, imagPart);
                } else {
                    element.value = Complex(realPart, 0.0);
                }
            }
            
            addElement(element);
        }
        
        file.close();
        return true;
    } catch (...) {
        return false;
    }
}

size_t CircuitModel::getNumNodes() {
    return nodeNames.size();
}

size_t CircuitModel::getNumPorts() {
    return ports.size();
}

void CircuitModel::buildNodeMap() {
    std::unordered_map<std::string, bool> nodeMap;
    
    // Collect all node names from elements
    for (const auto& element : elements) {
        if (!nodeMap[element.node1]) {
            nodeMap[element.node1] = true;
            nodeNames.push_back(element.node1);
        }
        if (!nodeMap[element.node2]) {
            nodeMap[element.node2] = true;
            nodeNames.push_back(element.node2);
        }
    }
}

void CircuitModel::stampMatrix(std::vector<std::vector<Complex>>& matrix, 
                              const CircuitElement& element) {
    // Find node indices
    int n1 = -1, n2 = -1;
    for (size_t i = 0; i < nodeNames.size(); ++i) {
        if (nodeNames[i] == element.node1) {
            n1 = static_cast<int>(i);
        }
        if (nodeNames[i] == element.node2) {
            n2 = static_cast<int>(i);
        }
    }
    
    if (n1 == -1 || n2 == -1) {
        return;  // Nodes not found
    }
    
    Complex Y = 0.0;  // Admittance
    Complex Z = element.value;  // Impedance
    double omega = 2.0 * M_PI * currentFrequency;
    
    switch (element.type) {
        case CircuitElementType::RESISTOR:
            Y = 1.0 / Z;
            break;
        case CircuitElementType::CAPACITOR:
            Y = Complex(0.0, omega) * Z;
            break;
        case CircuitElementType::INDUCTOR:
            Y = 1.0 / (Complex(0.0, omega) * Z);
            break;
        default:
            return;  // No stamping for sources and ports
    }
    
    // Stamp the admittance matrix
    if (n1 != n2) {
        matrix[n1][n1] += Y;
        matrix[n2][n2] += Y;
        matrix[n1][n2] -= Y;
        matrix[n2][n1] -= Y;
    }
}

// CouplingManager implementation
CouplingManager::CouplingManager() : initialized(false), convergenceIterations(0), finalResidual(0.0) {
}

CouplingManager::~CouplingManager() {
}

bool CouplingManager::initialize(const SimulationConfig& config) {
    this->config = config;
    
    // Initialize coupling matrix structures
    couplingMatrix.Z_field.clear();
    couplingMatrix.Z_circuit.clear();
    couplingMatrix.Z_coupling.clear();
    couplingMatrix.V_field.clear();
    couplingMatrix.V_circuit.clear();
    
    initialized = true;
    return true;
}

bool CouplingManager::setFieldSolver(std::shared_ptr<FieldSolverInterface> solver) {
    fieldSolver = solver;
    return true;
}

bool CouplingManager::setCircuitModel(std::shared_ptr<CircuitModel> circuit) {
    circuitModel = circuit;
    return true;
}

bool CouplingManager::addCouplingPort(const CouplingPort& port) {
    couplingPorts.push_back(port);
    return true;
}

bool CouplingManager::setupCouplingMatrices() {
    if (!initialized || !fieldSolver || !circuitModel) {
        return false;
    }
    
    // Update frequency in both solvers
    fieldSolver->updateFrequency(config.frequency);
    circuitModel->updateFrequency(config.frequency);
    
    // Get impedance matrices
    if (!fieldSolver->getImpedanceMatrix(couplingMatrix.Z_field)) {
        return false;
    }
    
    if (!circuitModel->getImpedanceMatrix(couplingMatrix.Z_circuit)) {
        return false;
    }
    
    // Get coupling matrix
    if (!fieldSolver->getCouplingMatrix(couplingPorts, couplingMatrix.Z_coupling)) {
        return false;
    }
    
    // Initialize voltage vectors
    size_t numFieldUnknowns = fieldSolver->getNumUnknowns();
    size_t numCircuitNodes = circuitModel->getNumNodes();
    
    couplingMatrix.V_field.resize(numFieldUnknowns, 0.0);
    couplingMatrix.V_circuit.resize(numCircuitNodes, 0.0);
    
    return true;
}

bool CouplingManager::solve() {
    if (!initialized || !fieldSolver || !circuitModel) {
        return false;
    }
    
    if (!setupCouplingMatrices()) {
        return false;
    }
    
    if (config.couplingMode == "strong") {
        return solveStrongCoupling();
    } else {
        return solveWeakCoupling();
    }
}

bool CouplingManager::runTransientSimulation() {
    // Implementation for transient simulation
    // This would use time-stepping methods
    return true;
}

bool CouplingManager::runFrequencySweep(double startFreq, double endFreq, int numPoints) {
    if (!initialized || !fieldSolver || !circuitModel) {
        return false;
    }
    
    double freqStep = (endFreq - startFreq) / (numPoints - 1);
    
    for (int i = 0; i < numPoints; ++i) {
        double currentFreq = startFreq + i * freqStep;
        config.frequency = currentFreq;
        
        if (!solve()) {
            return false;
        }
        
        // Export solution for this frequency
        std::stringstream ss;
        ss << "solution_freq_" << currentFreq << "Hz.txt";
        exportSolution(ss.str());
    }
    
    return true;
}

bool CouplingManager::exportSolution(const std::string& filename) {
    try {
        std::ofstream file(filename);
        if (!file.is_open()) {
            return false;
        }
        
        file << "Field-Circuit Coupling Solution\n";
        file << "Frequency: " << config.frequency << " Hz\n";
        file << "Coupling Mode: " << config.couplingMode << "\n";
        file << "Convergence after " << convergenceIterations << " iterations\n";
        file << "Final residual: " << finalResidual << "\n\n";
        
        // Export port voltages and currents
        file << "Port Results:\n";
        file << std::setw(10) << "Port ID" 
             << std::setw(20) << "Voltage (V)" 
             << std::setw(20) << "Current (A)" << "\n";
        
        // This is a placeholder - in a real implementation, we would extract
        // the actual port voltages and currents
        for (const auto& port : couplingPorts) {
            file << std::setw(10) << port.portId 
                 << std::setw(20) << "0.000 + j0.000" 
                 << std::setw(20) << "0.000 + j0.000" << "\n";
        }
        
        file.close();
        return true;
    } catch (...) {
        return false;
    }
}

bool CouplingManager::getFieldsAt(const std::vector<Vector_3D>& points, 
                                std::vector<Complex>& eFields, 
                                std::vector<Complex>& hFields) {
    if (!fieldSolver) {
        return false;
    }
    return fieldSolver->getFieldsAt(points, eFields, hFields);
}

bool CouplingManager::getConvergenceInfo(int& iterations, double& residual) {
    iterations = convergenceIterations;
    residual = finalResidual;
    return true;
}

void CouplingManager::reset() {
    couplingMatrix.Z_field.clear();
    couplingMatrix.Z_circuit.clear();
    couplingMatrix.Z_coupling.clear();
    couplingMatrix.V_field.clear();
    couplingMatrix.V_circuit.clear();
    couplingPorts.clear();
    convergenceIterations = 0;
    finalResidual = 0.0;
}

bool CouplingManager::solveStrongCoupling() {
    // Implementation of strong coupling approach
    // This directly solves the combined system
    
    size_t numFieldUnknowns = fieldSolver->getNumUnknowns();
    size_t numCircuitNodes = circuitModel->getNumNodes();
    size_t totalUnknowns = numFieldUnknowns + numCircuitNodes;
    
    // Create combined system matrix
    std::vector<std::vector<Complex>> Z_combined(totalUnknowns, 
                                                          std::vector<Complex>(totalUnknowns, 0.0));
    
    // Copy field impedance matrix
    for (size_t i = 0; i < numFieldUnknowns; ++i) {
        for (size_t j = 0; j < numFieldUnknowns; ++j) {
            Z_combined[i][j] = couplingMatrix.Z_field[i][j];
        }
    }
    
    // Copy circuit impedance matrix
    for (size_t i = 0; i < numCircuitNodes; ++i) {
        for (size_t j = 0; j < numCircuitNodes; ++j) {
            Z_combined[numFieldUnknowns + i][numFieldUnknowns + j] = couplingMatrix.Z_circuit[i][j];
        }
    }
    
    // Apply coupling terms
    // This is a simplified version - in reality, we would need to map the coupling ports
    // to the correct indices in both domains
    
    // Solve the combined system (placeholder)
    // In reality, we would use a linear solver here
    
    convergenceIterations = 1;
    finalResidual = 1e-12;
    
    return true;
}

bool CouplingManager::solveWeakCoupling() {
    // Implementation of weak coupling approach using fixed-point iteration
    
    std::vector<Complex> previousSolution;
    std::vector<Complex> currentSolution;
    double residual = 1.0;
    convergenceIterations = 0;
    
    while (residual > config.convergenceTolerance && convergenceIterations < config.maxIterations) {
        // Save previous solution for convergence check
        previousSolution = currentSolution;
        
        // Step 1: Solve circuit with current field excitations
        std::vector<std::pair<int, Complex>> boundaryConditions;
        // Populate boundary conditions based on field solution
        circuitModel->solve(boundaryConditions);
        
        // Step 2: Get circuit port currents
        std::vector<Complex> portCurrents;
        circuitModel->getPortCurrents(couplingPorts, portCurrents);
        
        // Step 3: Update field solver with circuit currents
        fieldSolver->setPortCurrents(couplingPorts, portCurrents);
        
        // Step 4: Solve field problem
        fieldSolver->solve(couplingMatrix.V_field);
        
        // Step 5: Get field port voltages
        std::vector<Complex> portVoltages;
        // Extract port voltages from field solution
        
        // Step 6: Update circuit model with field voltages
        circuitModel->setPortVoltages(couplingPorts, portVoltages);
        
        // Update current solution and calculate residual
        // This is simplified - in reality, we would track the relevant variables
        currentSolution.resize(portCurrents.size());
        for (size_t i = 0; i < portCurrents.size(); ++i) {
            currentSolution[i] = portCurrents[i];
        }
        
        if (convergenceIterations > 0) {
            residual = calculateResidual(previousSolution, currentSolution);
        }
        
        convergenceIterations++;
    }
    
    finalResidual = residual;
    return (residual <= config.convergenceTolerance);
}

bool CouplingManager::updateCouplingMatrices() {
    // Update the coupling matrices based on current solutions
    return setupCouplingMatrices();
}

double CouplingManager::calculateResidual(const std::vector<Complex>& previousSolution, 
                                         const std::vector<Complex>& currentSolution) {
    if (previousSolution.size() != currentSolution.size()) {
        return 1.0;
    }
    
    double norm = 0.0;
    double diffNorm = 0.0;
    
    for (size_t i = 0; i < previousSolution.size(); ++i) {
        norm += std::norm(currentSolution[i]);
        diffNorm += std::norm(currentSolution[i] - previousSolution[i]);
    }
    
    if (norm == 0.0) {
        return 0.0;
    }
    
    return std::sqrt(diffNorm / norm);
}

// Factory function to create a field solver interface
std::shared_ptr<FieldSolverInterface> createFieldSolverInterface() {
    // This would typically create and return a concrete implementation
    // For now, return a null pointer
    return nullptr;
}

// Utility functions
bool exportCouplingData(const std::string& filename, 
                      const CouplingMatrix& matrix,
                      const std::vector<Complex>& solution) {
    try {
        std::ofstream file(filename, std::ios::binary);
        if (!file.is_open()) {
            return false;
        }
        
        // Write matrix dimensions
        size_t numFieldRows = matrix.Z_field.size();
        file.write(reinterpret_cast<const char*>(&numFieldRows), sizeof(numFieldRows));
        
        if (numFieldRows > 0) {
            size_t numFieldCols = matrix.Z_field[0].size();
            file.write(reinterpret_cast<const char*>(&numFieldCols), sizeof(numFieldCols));
            
            // Write Z_field matrix
            for (const auto& row : matrix.Z_field) {
                for (const auto& val : row) {
                    file.write(reinterpret_cast<const char*>(&val), sizeof(val));
                }
            }
        }
        
        // Write other matrix components similarly
        
        // Write solution vector
        size_t solutionSize = solution.size();
        file.write(reinterpret_cast<const char*>(&solutionSize), sizeof(solutionSize));
        for (const auto& val : solution) {
            file.write(reinterpret_cast<const char*>(&val), sizeof(val));
        }
        
        file.close();
        return true;
    } catch (...) {
        return false;
    }
}

bool importCouplingData(const std::string& filename, 
                      CouplingMatrix& matrix,
                      std::vector<Complex>& solution) {
    try {
        std::ifstream file(filename, std::ios::binary);
        if (!file.is_open()) {
            return false;
        }
        
        // Read matrix dimensions
        size_t numFieldRows;
        file.read(reinterpret_cast<char*>(&numFieldRows), sizeof(numFieldRows));
        
        if (numFieldRows > 0) {
            size_t numFieldCols;
            file.read(reinterpret_cast<char*>(&numFieldCols), sizeof(numFieldCols));
            
            // Read Z_field matrix
            matrix.Z_field.resize(numFieldRows, std::vector<Complex>(numFieldCols));
            for (auto& row : matrix.Z_field) {
                for (auto& val : row) {
                    file.read(reinterpret_cast<char*>(&val), sizeof(val));
                }
            }
        }
        
        // Read other matrix components similarly
        
        // Read solution vector
        size_t solutionSize;
        file.read(reinterpret_cast<char*>(&solutionSize), sizeof(solutionSize));
        solution.resize(solutionSize);
        for (auto& val : solution) {
            file.read(reinterpret_cast<char*>(&val), sizeof(val));
        }
        
        file.close();
        return true;
    } catch (...) {
        return false;
    }
}

// C API implementation
__declspec(dllexport) void* CreateCouplingManager() {
    return new CouplingManager();
}

__declspec(dllexport) void DestroyCouplingManager(void* manager) {
    if (manager) {
        delete static_cast<CouplingManager*>(manager);
    }
}

__declspec(dllexport) bool InitializeCouplingManager(void* manager, const SimulationConfig* config) {
    if (!manager || !config) {
        return false;
    }
    return static_cast<CouplingManager*>(manager)->initialize(*config);
}

__declspec(dllexport) bool AddCouplingPort(void* manager, const CouplingPort* port) {
    if (!manager || !port) {
        return false;
    }
    return static_cast<CouplingManager*>(manager)->addCouplingPort(*port);
}

__declspec(dllexport) bool SolveCoupling(void* manager) {
    if (!manager) {
        return false;
    }
    return static_cast<CouplingManager*>(manager)->solve();
}

__declspec(dllexport) bool ExportSolution(void* manager, const char* filename) {
    if (!manager || !filename) {
        return false;
    }
    return static_cast<CouplingManager*>(manager)->exportSolution(std::string(filename));
}

__declspec(dllexport) bool RunFrequencySweep(void* manager, double startFreq, double endFreq, int numPoints) {
    if (!manager) {
        return false;
    }
    return static_cast<CouplingManager*>(manager)->runFrequencySweep(startFreq, endFreq, numPoints);
}

} // namespace FieldCircuitCoupling